1. Field of the Invention
The present invention relates to vehicle control devices that perform vehicle-behavior control, such as front-rear driving-force distribution control and left-right driving-force distribution control, while realizing maximum traction performance.
2. Description of the Related Art
In recent years, vehicles are equipped with various traction control devices that control engine output in accordance with a driving condition.
For example, Japanese Unexamined Patent Application Publication No. 11-59366 discloses a technology in which a road-surface friction coefficient generated on vehicle wheels and lateral forces generated on the wheels are estimated so as to calculate maximum front-rear forces of the wheels on the basis of these estimated road-surface friction coefficient and lateral forces. Based on the calculated maximum front-rear forces, driving forces or braking forces applied to the wheels are controlled.
When a vehicle equipped with a driving-force control function as disclosed in Japanese Unexamined Patent Application Publication No. 11-59366 has a front-rear driving-force distribution control function and a left-right driving-force distribution control function, a permissible engine output value is unfavorably determined by a drive shaft whose front-rear driving force distribution is excessive with respect to dynamic ground-load distribution or a grip limit of inside turning wheels. Therefore, such a vehicle is problematic in that it cannot realize maximum traction performance where each wheel is utilized at full.